The introduction of hybrid electric vehicles, such as the Toyota Prius and Chevrolet Volt, has provided numerous examples of hybrid power systems wherein an internal combustion engine and a battery-powered electric motor are used to power a load. These systems are designed to rely solely on the electric motor, solely on the internal combustion engine, or on a combination of output from the electric motor and the engine to drive the load, depending upon demand. These systems incorporate an electrical generator that may be driven by the internal combustion engine during cruising, and by the vehicle momentum during regenerative braking, to generate electricity used to recharge the battery.
What is needed is a hybrid power system capable of delivering hydraulic power and electric power to drive a load. There is also a need for improved energy storage efficiency in the context of a hybrid power system.